In recent years, the size of solid state imaging devices for mobile cameras to be installed in, for example, cellular phones have been reduced, and solid state imaging devices whose pixel size is equal to or less than 2 μm are in use.
In order to achieve practical use of an imaging lens whose performance is sufficient for solid state imaging devices with such a small pixel size, four lenses need to be provided, and aberrations to be sufficiently corrected.
An imaging lens using four lenses is disclosed in the following patent literature:
Patent Literature 1: Unexamined Japanese Patent Application KOKAI Publication No. 2002-365529